brushed esc multi set up

[John Laverick]

Hi Guys, Iv'e dug out my Tony Nijhuis Lancaster for renovation, I've decided to leave the brushed motors in but I've give them each a seperate ESC and battery. Would I be right in removing the red wires from three of them, and leaving one to power 5 mini servos, or would a seperate power source be recommended?

Appreciate your help

John

[Frank Skilbeck]

Depends on the battery and ESC BEC, if the BEC is up for it, and as it's only 5 mini servos a 3A one should be fine.

Can't understand why you'd want to put 4 battery/brushed ESCs in though, unless you want to control them separately. With the set up you are proposing then one motor/battery combination will reach LVC before the others with the potential for one motor to cut or slow down.

[John Laverick]

Fair point Frank, I just happen to have four brushed esc's to use. Suppose I could still use the 4 esc's and two batteries, one running the inner motors and one running the outer. However if I did that would both motors get the same voltage from the battery? for instance if I used one 3s on the inners would they recieve only half the voltage if paralled? The motors are 7.2 volt 480 BB's.

If the voltage is halved when paralled, would I need to use a 4s so both motors get 7.1 volts each with no change to the amps?

John

[Simon Chaddock]

John

Not quite sure of your meaning.

Motors in parallel would mean each will see the full battery voltage. Motors is series would mean the battery voltage was shared between them but I would definitely not recommend running brushed motors is series as they react against each other.

So one battery feeding both ESCs (in parallel) and another battery the other ESCs.

Or you could use a single big battery and feed all four ESCs in parallel then you would have no worries about one motor slowing before the others.

The last point is ESCs do not necessarily have the same throttle response, particularly at part throttle. It might not be a problem but it would need checking.

[John Laverick]

Thanks Simon,

what I'm concerned about is what size battery I would use? if the motors are 7.2 volts would I have to use a 2 s on each pair of motors, and parallel the batteries to get a better amperage, what size single big battery would I need to use?

Am I over thinking things, or just not thinking at all!!!!!!!!! Brushless is much easier

[Frank Skilbeck]

One other thing to check with using 4 ESCs is that they may not work off one Rx feed, in that splitting the PPM signal into 4 may be too weak for then ESC to recognise, so you may need to plug them into the Rx singley or in pairs (i.e. inner and outer as Simon notes).

The size of battery would depend on the total amps, C rating and flight duration, I'd go for as big a 2s battery that fits the plane and run all the ESCs off that, the only reason to use 2 smaller batteries in parrallel would be if you had another application for that size battery.

[John Laverick]

Ok, thanks Frank, if I stick an alternative power source for the RX then, would that not negate the problem with the ESC's recognising each other?

[Frank Skilbeck]

John, it's not that the Rx's would recognise each other just the signal from the Rx split 4 ways may not be recognised by the ESCs, I had this happen with 2 escs Y leaded together and then Y leaded with a servo to the Rx, the ESCs wouldn't work and I could only get them to work by plugging the ESCs on a Y lead direct into the Rx. It's the strength of the position signal from the Rx (which comes from the controller chip) rather than the power supply, but try it you may find your Rx/ESC combination allows all 4 to be controlled from one Rx output.